1. Field of the Invention
The present invention is generally directed to delivering liquid compositions to an interior site in the body. More particularly, this invention relates to delivering and draining compositions to and from a human patient at high flow rates to perform peritoneal dialysis under sterile conditions.
Patients afflicted with end stage renal disease where kidney transplantation is unavailable may be treated by hemodialysis or peritoneal dialysis to remove toxic products from the patient's blood. Both techniques operate by the principles of diffusion across semipermeable membranes. In the case of peritoneal dialysis, the membrane that is used is the patient's peritoneal membrane. In order to perform dialysis, a dialyzing solution or dialysate is drained into the peritoneal cavity and remains in the cavity for a dwell period of usually four to six hours. The dialyzing solution typically comprises an electrolyte component to reduce loss of electrolytes and a sugar component which acts as an anosmotic ingredient, removing water from the patient along with normal metabolic products such as urea, uric acid and creatinine. At the end of the dwell period, spent dialyzing solution is drained from the cavity back to the bag and the cavity refilled with fresh solution.
One serious drawback to peritoneal dialysis, which has limited its use, is that the peritoneal cavity is particularly subject to infection. Conventional peritoneal dialysis systems usually employ catheters which are implanted transcutaneously through the patient's abdomen. This exposure naturally increases the risk of contamination through the exposed, exterior end of the catheter. The tubing sets used to infuse solution into the peritoneum may also be a source of contamination. While the use of subcutaneously implanted septum-type ports has been suggested (such ports would be accessed with needles which reduces the chance of infection), the access with small bore non-coring needles places a flow restriction in the system which reduces the flow rate below the rate achieved by transcutaneous catheters. Such small bore access needles with relatively low flow rates prolong the exchange time and create additional patient discomfort.
2. Description of the Background Art
Conventional peritoneal dialysis tubing sets and components are described in U.S. Pat. Nos. 4,306,976; 4,396,382; 5,250,041; 5,334,139; 5,338,293; and 5,423,768. U.S. Pat. No. 4,184,497 describes an implantable catheter having an enlarged hollow portion which can be punctured to receive a sterile access needle. U.S. Pat. No. 4,496,349 describes a septum-type transcutaneous access port.